admin: reject clients unless their UID matches the current UID

The admin protocol RPC messages are only intended for use by the user
running the daemon. As such they should not be allowed for any client
UID that does not match the server UID.

Fixes CVE-2019-10132

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
(cherry picked from commit 96f41cd765c9e525fe28ee5abbfbf4a79b3720c7)

diff --git a/src/admin/admin_server_dispatch.c b/src/admin/admin_server_dispatch.c
index b78ff902c0fa7f3b410f3d7e7d0dcf743a8a8db9..9f25813ae341a303b86ba1f49faabd016415a349 100644 (file)
--- a/src/admin/admin_server_dispatch.c
+++ b/src/admin/admin_server_dispatch.c
@@ -66,6 +66,28 @@ remoteAdmClientNew(virNetServerClientPtr client ATTRIBUTE_UNUSED,
                    void *opaque)
 {
     struct daemonAdmClientPrivate *priv;
+    uid_t clientuid;
+    gid_t clientgid;
+    pid_t clientpid;
+    unsigned long long timestamp;
+
+    if (virNetServerClientGetUNIXIdentity(client,
+                                          &clientuid,
+                                          &clientgid,
+                                          &clientpid,
+                                          &timestamp) < 0)
+        return NULL;
+
+    VIR_DEBUG("New client pid %lld uid %lld",
+              (long long)clientpid,
+              (long long)clientuid);
+
+    if (geteuid() != clientuid) {
+        virReportRestrictedError(_("Disallowing client %lld with uid %lld"),
+                                 (long long)clientpid,
+                                 (long long)clientuid);
+        return NULL;
+    }
 
     if (VIR_ALLOC(priv) < 0)
         return NULL;